A metallic element such as molybdenum, niobium, tantalum and tungsten is known as an essential element of refractory metal which can be used at temperatures as high as not lower than 1,000.degree. C. Among these metallic elements, molybdenum forms a Laves structure silicide with silicon and at least one element belonging to the group 8A such as nickel, cobalt and iron. The silicide is represented by the chemical formula X.sub.3 Mo.sub.2 Si or XMoSi(in which X represents at least one element selected from the group consisting of nickel, cobalt, iron, etc.). As practical alloys containing such a silicide, there have been known Ni-base alloy and Co-base alloy described in "Wear and corrosion resistant alloy" (U.S. Pat. No. 3,839,024). These alloys are widely used for thermal spraying.
In recent years, for internal combustion engine, higher combustion efficiency, switching to substitute fuel, etc. have been keenly desired. To make those possible, mechanical parts constituting such an internal combustion engine must withstand even severer conditions of temperature, load and atmosphere.
However, the foregoing prior art alloys are disadvantageous in that they cannot meet these requirements. In particular, sliding mechanical parts are expected to withstand high temperature, nonlubricating and corrosive atmospheres at the same time, and the existing wear resistant materials become unfit for use more occasionally.